Electronic device for wireless communications, and wireless communication method

ABSTRACT

This disclosure relates to an electronic device for wireless communications, and a wireless communication method. The electronic device comprises one or more processors, wherein each processor is configured to respectively conduct space-domain filtering on received signals of a plurality of antennas, respectively; estimate the frequency shift of corresponding received signals based on the signals, on which space-domain filtering is conducted, of various antennas; estimate, according to the estimated frequency shift and a parameter of the space-domain filtering, a Doppler frequency shift generated by the relative motion between transceiving ends of the received signals and a carrier frequency offset generated by frequency inconsistency of the transceiving ends; and conduct frequency preprocessing on sent signals of the antennas according to the estimated Doppler frequency shift, and/or control to feed back information related to the estimated Doppler frequency shift to a signal sending end.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. application Ser. No.15/760,802, filed Mar. 16, 2018, which is based on PCT filingPCT/CN2016/099686, filed Sep. 22, 2016, which claims the priority toChinese Patent Application No. 201510617374.2, filed on Sep. 24, 2015,the entire contents of each are incorporated herein by reference.

FIELD

Embodiments of the present disclosure relate to wireless communication,and in particular to an electronic device for wireless communication anda wireless communication method.

BACKGROUND

In a fast time-varying channel environment (such as a high speedrailway), the performance of a wireless communication system may beaffected by a Doppler effect caused by a relative movement between areceiving end and a transmitting end. In addition, in a wirelesscellular mobile communication system, to restrain a carrier frequencyoffset generated by frequency inconsistency between receiving and thetransmitting ends, a frequency of a local oscillator of a receiver isgenerally adjusted by measuring a frequency offset of a received signalby using an automatic frequency calibration technology, thereby thefrequency generated by the local oscillator is synchronized with thecarrier frequency of the received signal. In a fast time-varying channelenvironment, an effect on the received signal caused by the carrierfrequency offset generated by the frequency inconsistency of thereceiving and transmitting ends has a manner similar to that of aneffect on the received signal caused by the Doppler shift generated bythe relative movement between the receiving and transmitting ends.Therefore, the frequency offset parameters estimated at the receivingend by the automatic frequency calibration technology essentiallyinclude both the carrier frequency offset generated by the frequencyinconsistency of the receiving and transmitting ends and the Dopplershift generated by the relative movement between the receiving andtransmitting ends.

SUMMARY

Generally, in order to reduce a Doppler effect at a receiving end of asignal, frequency preprocessing is performed on a transmission signal ata transmitting end of the signal with a Doppler parameter estimated froma received signal. In performing frequency preprocessing on thetransmission signal at the transmitting end, the parameter to be used isa Doppler shift instead of a carrier frequency offset generated byfrequency inconsistency of the receiving and transmitting ends. Ingeneral, a difference between a frequency of an oscillator at thereceiving end and a frequency of an oscillator at the transmitting endis unavoidable. Thus, in performing frequency preprocessing on atransmission signal with a related technology, a frequency offsetgenerated by the frequency inconsistency of the receiving andtransmitting ends and a Doppler shift generated by a relative movementbetween the receiving and transmitting ends cannot be distinguished fromeach other, so an effect on the performance of a receiver caused by theDoppler shift generated by the relative movement between the receivingand transmitting ends cannot be restrained.

In another aspect, a wireless network coverage is achieved by way oftransmitting a signal by a base station in a wireless cellular system.The Doppler effect is related to both a relative moving speed betweenthe receiving and transmitting ends and an arrival angle of the receivedsignal. So a Doppler frequency changes greatly when a mobile stationmoves close to a base station and performs a handover between two basestations. This is one of main reasons for occurrence of the call dropsand handover failures in a fast time-varying channel environment in therelated technologies.

In the following, an overview of embodiments of the present disclosureis given to provide basic understanding to some aspects of the presentdisclosure. It should be understood that this overview is not anexhaustive overview of the present disclosure. It is neither intended todetermine a critical or important part of the present disclosure, nor tolimit the scope of the present disclosure. An object of the overview isonly to give some concepts in a simplified manner, which serves as apreface of a more detailed description later.

According to an aspect of the present disclosure, an electronic devicefor wireless communication includes at least one processor. Theprocessor is configured to: perform spatial filtering respectively onreceived signals of multiple antennas; estimate, based on thespatially-filtered signal of each of the antennas, a frequency offset ofa corresponding received signal; estimate, based on parameters of thespatial filtering and the estimated frequency offset, a Doppler shiftcaused by a relative movement between a receiving end and a transmittingend of the received signal and a carrier frequency offset caused byfrequency inconsistency of the receiving end and the transmitting end;and perform frequency preprocessing on a transmission signal of theantenna based on the estimated Doppler shift, and/or perform control tofeed back information on the estimated Doppler shift to the transmittingend of the received signal.

According to another aspect of the present disclosure, a wirelesscommunication method includes: performing spatial filtering respectivelyon received signals of multiple antennas; estimating, based on thespatially-filtered signal of each of the antennas, a frequency offset ofa corresponding received signal; estimating, based on parameters of thespatial filtering and the estimated frequency offset, a Doppler shiftcaused by a relative movement between a receiving end and a transmittingend of the received signal and a carrier frequency offset caused byfrequency inconsistency of the receiving end and the transmitting end;and performing frequency preprocessing on a transmission signal of theantenna based on the estimated Doppler shift, and/or performing controlto feed back information on the estimated Doppler shift to thetransmitting end of the received signal.

The solutions according to the embodiments of the present disclosure arebeneficial to improve the throughput performance of a wirelesscommunication system in a fast time-varying channel environment.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure may be better understood with reference to thedescription made in conjunction with the drawings hereinafter. Same orsimilar components are identified by same or similar referencecharacters throughout the drawings. The drawings together with thedetailed description below are incorporated in and form a part of thespecification, for further illustrating preferred embodiments of thepresent disclosure with examples and explaining the principle andadvantages of the present disclosure. In the drawings:

FIG. 1 is a block diagram showing a configuration example of anelectronic device for wireless communication according to an embodimentof the present disclosure;

FIG. 2 is a block diagram showing a configuration example of anelectronic device for wireless communication according to anotherembodiment;

FIG. 3 is a flowchart showing a process example of a wirelesscommunication method according to an embodiment of the presentdisclosure;

FIG. 4 is a flowchart showing a process example of a wirelesscommunication method according to another embodiment;

FIG. 5 is a flowchart showing a process example of a wirelesscommunication method according to yet another embodiment;

FIG. 6 is a block diagram showing a configuration example of a userequipment according to an exemplary embodiment;

FIG. 7 is a block diagram showing a configuration example of a basestation according to an exemplary embodiment;

FIG. 8 is a schematic diagram for illustrating an informationinteraction process between a base station and a user equipment in anexemplary embodiment;

FIG. 9 is a block diagram showing a configuration example of anelectronic device for wireless communication according to an embodimentof the present disclosure;

FIG. 10 is a block diagram showing an exemplary structure of a computerimplementing the method and device according to the present disclosure;

FIG. 11 is a block diagram showing an example of a schematicconfiguration of a smart phone to which a technology according to thepresent disclosure can be applied;

FIG. 12 is a block diagram showing an example of a schematicconfiguration of an evolved base station (eNB) to which a technologyaccording to the present disclosure can be applied; and

FIG. 13 is a block diagram of an example of a schematic configuration ofan automobile navigation device to which a technology according to thepresent disclosure can be applied.

DETAILED DESCRIPTION OF EMBODIMENTS

Hereinafter, embodiments of the present disclosure are described inconjunction with the drawings. Elements and features described in adrawing or an embodiment of the present disclosure can be combined withelements and features shown in one or more of other drawings orembodiments. It should be noted that, for clarity, it is omittedrepresentations and descriptions of components and processing which areirrelevant to the present disclosure and known by those skilled in theart in the drawings and the specification.

As shown in FIG. 1, an electronic device 100 for wireless communicationaccording to an embodiment includes at least one processor 110. Theprocessor 110 includes a filtering unit 111, a first estimation unit113, a second estimation unit 115 and a preprocessing/control unit 117.

It should be noted that, although the filtering unit 111, the firstestimation unit 113, the second estimation unit 115 and thepreprocessing/control unit 117 of the processor 110 are shown withseparate dashed blocks in the figure, functions of these units may beimplemented by the processor 110 as a whole, and are not necessarilyimplemented by actual separate components in the processor 110. Inaddition, although the processor 110 is shown with one block in thefigure, the electronic device 100 may include multiple processors, andthe functions of the filtering unit 111, the first estimation unit 113,the second estimation unit 115 and the preprocessing/control unit 117may be distributed in multiple processors. In this case, these functionsare performed by the multiple processors in a cooperative way.

The filtering unit 111 is configured to perform spatial filtering onreceived signals of multiple antennas.

Specifically, the spatial filtering performed on the signals receivedvia the multiple antennas may be represented as:

r=Fy  Equation 1

where y is a vector of received signal with a length of N, r is a vectorof filtered signal with a length of N, F is a spatial filtering matrixwith a size of N×N, and elements on a k-th row of the spatial filteringmatrix correspond to a k-th spatial filter coefficient. The k-th rowincludes N elements. The spatial filter coefficients can be determinedwith a method such as minimum equivalent wavenumber spectrum extension.

It should be noted that, the object of the spatial filtering here is toprovide a necessary signal dimension for a joint estimation in thesubsequent processing. The joint estimation is performed for a Dopplershift generated by a relative movement between a receiving end and atransmitting end and a carrier frequency offset generated by frequencyinconsistency of the receiving end and the transmitting end.

The first estimation unit 113 is configured to estimate, based on thespatially-filtered signal of the each of the antennas, a frequencyoffset of a corresponding received signal.

The first estimation unit 113 may estimate the frequency offset invarious manners known in the art. For example, according to anembodiment, the first estimation unit 113 may estimate the frequencyoffset of the received signal by using an estimation method based ontraining sequence or a blind estimation method based on signalstatistical information, but the invention is not limited thereto.

It should be noted that, the frequency offset estimated by the firstestimation unit 113 may include a component of the Doppler shiftgenerated by a relative movement between the receiving and transmittingends of the signal and a component of the carrier frequency offsetgenerated by frequency inconsistency of the receiving and transmittingends. As mentioned above, the components of the above two types offrequency offset cannot be distinguished from each other according tothe related technologies, and sometimes a sum of the components of thetwo types of frequency offset is simply approximated as a Doppler shift(for example, referred to as an equivalent Doppler shift) for subsequentprocessing. In the solutions of the present disclosure, the componentsof the above two types of frequency offset can be estimated jointly,that is, the Doppler shift and the carrier frequency offset can berespectively estimated.

The second estimation unit 115 is configured to estimate the Dopplershift generated by the relative movement between the receiving andtransmitting ends of the received signal and the carrier frequencyoffset generated by frequency inconsistency of the receiving andtransmitting ends, based on the frequency offset estimated by the firstestimation unit 113 and the parameters of the spatial filteringperformed by the filtering unit 111.

Next, the estimations performed by the first estimation unit 113 andsecond estimation unit 115 are illustrated with reference with specificexamples. It should be understood that, the invention is not limited todetails described in the following examples.

Assuming that there are N antennas at the receiving end, andaccordingly, the filtering unit 111 performs spatial filteringrespectively on received signals of the antennas with N spatial filters.The first estimation unit 113 may obtain N frequency offset estimationparameters based on signals filtered by the filtering unit 111. Theparameters are represented as f_(d)=[f_(d) ¹ f_(d) ² . . . f_(d)^(N)]^(T), where f_(d) ^(n) is a frequency offset estimated from asignal filtered by the n-th spatial filter. It should be noted that,although the frequency offset of the received signal estimated by thefirst estimation unit 113 is represented with f_(d) ^(n) here, thefrequency offset f_(d) ^(n) contains both the component of the Dopplershift and the component of the carrier frequency offset (or, f_(d) ^(n)here can be understood as corresponding to the aforementioned equivalentDoppler shift).

As described above, when performing the estimation, the first estimationunit 113 may use training sequences and adopt a self-correlation-basedestimation algorithm or a cross-correlation-based estimation algorithm,or may adopt a blind frequency offset estimation algorithm. Theestimated parameter f_(d) ^(n) is not only related to the carrierfrequency offset f_(Δ) generated by frequency inconsistency of thereceiving and transmitting ends and the Doppler shift f_(d) generated bythe relative movement between the receiving and transmitting ends of thesignal, but also related to the n-th spatial filter parameter, and canbe represented as:

f _(d) cos(φ_(n)−θ_(R))+f _(Δ) =f _(d) ^(n)  Equation 2

where θ_(R) is a movement direction angle of the signal receiving endsuch as a mobile terminal, φ_(n) is a direction angle determined basedon the n-th spatial filter parameter, and φ_(n) may be calculated withthe following equation:

$\begin{matrix}{\phi_{n} = {\arccos \left( \frac{\lambda \overset{\_}{k_{n}}}{2\pi} \right)}} & {{Equation}\mspace{14mu} 3}\end{matrix}$

where λ is a wavelength, k_(n) is an average wavenumber corresponding tothe n-th spatial filter, that is:

$\begin{matrix}{\overset{\_}{k_{n}} = {{E\left\lbrack k_{n} \right\rbrack} = \frac{\int_{- \infty}^{+ \infty}{{{kS}_{n}(k)}{dk}}}{\int_{- \infty}^{+ \infty}{S_{n}\mspace{11mu} (k)\; {dk}}}}} & {{Equation}\mspace{14mu} 4}\end{matrix}$

where S_(n)(k) is a wavenumber spectrum calculated with the followingequation based on a shape of the antenna array and the n-th spatialfilter parameter, from an angle spectrum ρ_(n)(θ) corresponding to then-th spatial filter parameter, that is

$\begin{matrix}{{S_{n}(k)} = {{{\rho_{n}(\theta)}{\frac{d\; \theta}{dk}}} = {{\frac{1}{\sqrt{k_{0}^{2} - k^{2}}}{\rho_{n}(\theta)}} = {\frac{1}{k_{0}{{\sin \left( {\theta - \theta_{R}} \right)}}}{\rho_{n}(\theta)}}}}} & {{Equation}\mspace{14mu} 5}\end{matrix}$

where k₀=2π/λ.

Since φ_(n) depends on the spatial filter parameter, φ_(n) is a knownparameter if the spatial filter parameter is determined. Therefore,there are only two variables to be solved in Equation 2, i.e., f_(Δ) andf_(d).

In other words, according to an embodiment, the second estimation unit115 may estimate the Doppler shift f_(d) and the carrier frequencyoffset f_(Δ) based on a relation that the frequency offset f_(d) ^(n) isa linear combination of the Doppler shift Id and the carrier frequencyoffset f_(Δ). The relation of the linear combination may be determinedbased on a signal-to-noise ratio of respectively spatially-filteredsignal of the multiple antennas, the direction angle φ_(n) for therespective spatial filtering and the direction angle θR of the relativemovement between the receiving and transmitting ends of the receivedsignal.

In addition, a binary N-dimensional signal vector f_(d) may beconstructed based on Equation 2, and binary parameters (f_(Δ) and f_(d))may be estimated jointly with a weighted least square method as follows:

f _(Δ) f _(d)=(A ^(T) wA)⁻¹ A ^(T) wf _(d)  Equation 6

where A is an observation matrix, and w is an estimation weightingmatrix. The weighting matrix is adopted because it is not necessarilythe case that each of all the signals outputted by the N spatial filterscontains a useful signal.

The observation matrix A may be represented as:

$\begin{matrix}{A = \begin{bmatrix}1 & {\cos \left( {\phi_{1} - \theta_{R}} \right)} \\1 & {\cos \left( {\phi_{2} - \theta_{R}} \right)} \\\vdots & \vdots \\1 & {\cos \left( {\phi_{N} - \theta_{R}} \right)}\end{bmatrix}} & {{Equation}\mspace{14mu} 7}\end{matrix}$

The weighting matrix w may be represented as:

W=V ⁻¹  Equation 8

where V is an estimation error matrix for f_(d), which is a diagonalmatrix.

In other words, according to an embodiment, the second estimation unit115 may calculate f_(d) ^(n) as an estimated value of the Doppler shiftf_(d) and carrier frequency offset f_(Δ) by using the observation matrixand the weighting matrix. The observation matrix is related to thedirection angle φ_(n) and the direction angle θ_(R). In addition, theobservation matrix may be predetermined based on the direction anglesφ_(n) and θ_(R).

In another aspect, the weighting matrix may be related to thesignal-to-noise ratio of the spatially-filtered signal.

For example, an n-th element V_(n) on the diagonal line of theestimation error matrix V in Equation 8 may be represented as:

$\begin{matrix}{V_{n} = \frac{1}{{\pi^{2}{LT}_{s}^{2}} \star {SNR}_{n}}} & {{Equation}\mspace{14mu} 9}\end{matrix}$

where L is a training sequence period length, T_(s) is a symbol periodlength, and SNR_(n) is the signal-to-noise ratio of the signal filteredby the n-th spatial filter. SNR_(n) may be calculated with the followingequation:

$\begin{matrix}{{SNR}_{n} = {{SNR}_{n}^{\prime}\left( {1 + \sqrt{1 + \frac{1}{{SNR}_{n}^{\prime}}}} \right)}} & {{Equation}\mspace{14mu} 10}\end{matrix}$

where SNR_(n)′ is the signal-to-noise ratio of the signal filtered bythe n-th spatial filter estimated in a self-correlation way, and may berepresented as:

$\begin{matrix}{{SNR}_{n}^{\prime} = \frac{{{\sum\limits_{i = 1}^{K - L}{{r_{n}^{*}\left( {L + i} \right)}{r_{n}(n)}}}}^{2}}{\frac{1}{L - 1}{\sum\limits_{j = 1}^{L - 1}{{\sum\limits_{n = 1}^{K - L}{{r_{n}\left( {i + j} \right)}{r_{n}(i)}}}}^{2}}}} & {{Equation}\mspace{14mu} 11}\end{matrix}$

where r_(n)(i) is the signal filtered by the n-th spatial filter, and Kis a training sequence length. Values of the weighting matrix w need tobe calculated online since the weighting matrix w needs to be calculatedwith the received signal r(i) which is spatially filtered.

In other words, according to an embodiment, the weighting matrix isdetermined based on the signal-to-noise ratio of the spatially-filteredsignal estimated frame-by-frame.

In addition, in the above exemplary embodiments, the Doppler shift f_(d)and carrier frequency offset f_(Δ) may be estimated by using theweighted least square method, wherein the weighting may be performedbased on the signal-to-noise ratios of the spatially-filtered signals ofmultiple antennas. For example, the signal-to-noise ratio may beestimated in a self-correlation manner.

By using the weighting matrix, it is beneficial to improve robustnessand estimation accuracy of the parameter joint estimation algorithm in anon-ideal case.

Besides, according to an embodiment, the filtering unit 111, the firstestimation unit 113 and the second estimation unit 115 may be configuredto perform the above processing for the received signal frame-by-frame,to estimate the Doppler shift and the carrier frequency offset.

The electronic device according to the embodiment of the presentdisclosure may perform different subsequent processing by using theestimated Doppler shift and carrier frequency offset.

For example, the preprocessing/control unit 117 may be configured toperform a frequency preprocessing on a transmission signal of theantenna based on the estimated Doppler shift.

Specifically, the frequency preprocessing may include: performing thepreprocessing by adopting different Doppler shift estimations fordifferent spatial directions, and weighting the transmission signal withthe signal-to-noise ratios estimated for the spatial received signals.

In the following, an example manner for performing a frequencypreprocessing on a subsequent transmission signal with a Doppler shiftestimated based on a received signal is described. It should beunderstood that, the invention is not limited to details in the examplebelow.

In the case that f_(Δ) and f_(d) are estimated jointly, thepreprocessing/control unit 117 may perform the frequency preprocessingon the transmission signal by using parameters of the spatial filtersand the Doppler shift which is estimated with the received signal, thatis,

e _(n)(t)=V _(n) ⁻¹exp[−j2πf _(d) A(n,2)t]x(t)  Equation 12

where x(t) is a transmission information signal, e_(n)(t) is atransmission signal in a space corresponding to the n-th spatial filter,and A(n,2) is an element in the n-th row and the second column of theobservation matrix A.

In other words, when performing the frequency preprocessing on thetransmission signal, the preprocessing can be made by adopting differentDoppler estimation parameters for different spatial directions. Inaddition, the transmission signal may be weighted with thesignal-to-noise ratio parameter estimated by using the spatial receivedsignals, to adapt to a time-varying wireless channel environment.

Alternatively or additionally, the preprocessing/control unit 117 may befurther configured to control to feed back information on the estimatedDoppler shift to a transmitting end of the signal corresponding to theestimated Doppler shift.

The way that a receiving end of the signal estimates a Doppler parameterwith the received signal and then feeds back the parameter to thetransmitting end may be referred to as a closed-loop Doppler control.After receiving the parameter, the transmitting end may preprocess asignal to be transmitted with the parameter in the following signaltransmitting process, to reduce the Doppler effect on the signalreceived at the receiving end.

Moreover, the receiving end of the signal may further select, based onthe estimated Doppler shift, a filter corresponding to a signal with ahighest signal-to-noise ratio among the spatially-filtered signals, feedback a Doppler parameter corresponding to the selected filter to thetransmitting end to achieve the closed-loop Doppler control. Thereported Doppler parameter is, for example, f_(d)A(p,2), where p is anindex of the filter corresponding to the signal with the highestsignal-to-noise ratio among the spatially-filtered signals.

That is to say, the information on the estimated Doppler shift mayfurther contain a direction angle of spatial filtering corresponding tothe signal with the highest signal-to-noise ratio among thespatially-filtered signals.

A peer end communicating with the communication device according to theembodiment of the present disclosure may perform a frequencypreprocessing on the transmission signal in response to the feedbackinformation. For example, the preprocessing may be performed withdifferent Doppler estimation parameters for different spatialdirections, and the transmission signal may be further weighted with thesignal-to-noise ratios estimated with the respective spatial receivedsignals.

In another aspect, the electronic device according to an embodiment ofthe present disclosure may calibrate a frequency of a local frequencygenerator with the estimated carrier frequency offset. The embodiment isdescribed with reference to FIG. 2 below.

As shown in FIG. 2, an electronic device 200 for wireless communicationaccording to an embodiment includes at least one processor 200. Theprocessor 200 includes a filtering unit 211, a first estimation unit213, a second estimation 215, a preprocessing/control unit 217 and acalibration unit 219. The filtering unit 211, the first estimation unit213, the second estimation unit 215 and the preprocessing/control unit217 are respectively similar to the filtering unit 111, the firstestimation unit 113, the second estimation unit 115 and thepreprocessing/control unit 117 described above with reference to FIG. 1,for which the detailed descriptions are omitted here.

The calibration unit 219 is configured to calibrate a frequency of alocal frequency generator based on the carrier frequency offsetestimated by the second estimation unit 215, thereby reducing a carrierfrequency offset caused by frequency inconsistency of the receiving andtransmitting ends.

It should be noted that, the above electronic device 100 for wirelesscommunication and electronic device 200 for wireless communication mayoperate as a user equipment (UE). In this case, the electronic devices,for example, can perform the above processing on a downlink signal froma base station or a signal from another user equipment (for example, inthe case of direct communication between devices). However, theinvention is not limited thereto. For example, the embodiments of thepresent disclosure may be also applied at the base station side toestimate, for example, a Doppler shift and a carrier frequency offset ofan uplink signal from the user equipment, and to perform correspondingprocessing based on the estimating result.

In at least one embodiment of the present disclosure, the frequencyoffset generated by frequency inconsistency of the receiving andtransmitting ends and the Doppler shift generated by the relativemovement between the receiving and transmitting ends are estimatedjointly, by using the signals filtered by multiple spatial filters.During a transmission of a signal, a frequency preprocessing isperformed on the transmission signal by using the Doppler shift andfrequency offset parameters estimated from the received signal andparameters of the respective spatial filters, thereby improving thethroughput performance of the system in a fast time-varying channelenvironment.

Specifically, in the fast time-varying channel environment, a DopplerEffect of a signal at a receiving end cannot be suppressed with therelated technologies in the case that there is a frequency offsetgenerated by frequency inconsistency of the receiving and transmittingends. In at least one embodiment of the present disclosure, the Dopplereffect of the signal at the receiving end is suppressed by performingspatial filtering on the received signal, performing a binary parameter(f_(Δ) and f_(d)) joint estimation with the weighted least square methodand performing a frequency preprocessing on the transmission signalbased on corresponding spatial filter parameters. The embodiments of thepresent disclosure have one of the following technical effects.

1) It solves the problem in the related technologies that fast-changingDoppler shift parameter cannot be tracked in the case of a fasttime-varying channel environment, in particular in the case that a userequipment moves close to a base station and performs a handover. Theperformance of the system when moving close to the base station andperforming a handover is improved. Thus it solves the problem offrequent call drops and handover failures caused by that thefast-changing Doppler shift parameter cannot be tracked by the system inthe case of the fast time-varying channel environment.

2) It solves the problem in the related technologies that the Dopplereffect at the receiving end cannot be effectively suppressed with thefrequency preprocessing method in the case of inconsistent oscillatorfrequencies of the receiving end and the transmitting end, in the fasttime-varying channel environment.

3) During a signal transmission, by performing the frequencypreprocessing in different spatial domains with different spatial filterparameters, it solves a problem in the related technologies that afrequency preprocessing is difficult to be performed when a terminalsimultaneously communicates with two or more base transceiver stations.

4) With the closed-loop Doppler control, a probability of frequencytracking out-of-step is reduced, thereby improving the robustness of thesystem in the fast time-varying channel environment.

In addition, it should be noted that, the effectiveness of the solutionsof the invention is not limited to any existing wireless communicationsystem standard, and the expected effect of the present disclosure canbe achieved as long as antennas at the receiving end are array antennas.

Next, configuration examples of a user equipment and a correspondingbase station in which the closed-loop Doppler control can be performedaccording to exemplary embodiments of the present disclosure aredescribed respectively in conjunction with FIG. 6 and FIG. 7. It shouldbe understood that the invention is not limited to details in theexamples below.

As shown in FIG. 6, a received signal is firstly inputted to a spatialfiltering module 601. The spatial filtering module 601 performsspatial-filtering on the received signal, and output aspatially-filtered signal and spatial filtering parameter information.

The spatially-filtered signal is inputted to a frequency offsetestimation module 602 and a signal-to-noise ratio estimation module 603.The module 602 estimates frequency offsets in spatial domains,f_(d)=[f_(d) ¹ f_(d) ² f_(d) ^(N)]^(T), with a frequency offsetestimation algorithm, and outputs the frequency offsets to a parameterestimation module 606. The module 603 estimates signal-to-noise ratiosof the spatially-filtered signals and outputs the estimating results toa weighted matrix calculation module 604.

The module 604 calculates a weighted matrix w and outputs thecalculation result to the module 606.

Besides, the module 601 outputs the spatial filter parameter to anobservation matrix calculation module 605. The module 605 calculates anobservation matrix A and outputs the calculation result to the module606. The module 606 estimates parameters f_(Δ) and f_(d) with a weightedleast square algorithm and outputs f_(Δ) and f_(d) to a frequencypreprocessing module 608.

The module 608 performs a frequency preprocessing on transmissioninformation with f_(d). A reported Doppler parameter calculation module609 calculates a reported Doppler parameter with the outputs of themodule 603 and the module 606 and transmits the parameter to the basestation, to achieve a closed-loop Doppler control.

Optionally, a wavenumber transfer module 607 may perform a wavenumberspectrum transfer on the output signal of the module 601 by using theestimated f_(Δ) and f_(d), and outputs the transferring result to asubsequent receiver module for processing.

As shown in FIG. 7, the base station firstly extracts and analyzes theDoppler parameter reported by the terminal from the received signal witha closed-loop Doppler parameter analysis module 710. Then, a frequencypreprocessing module 711 performs a frequency preprocessing oninformation to be transmitted with the output of the module 710.

In addition, FIG. 8 is a schematic diagram showing signaling interactionbetween the base station and the terminal which perform the aboveclosed-loop Doppler control.

As shown in FIG. 8, in step S810, the base station transmits ameasurement control message to instruct the terminal to measure acurrent value of f_(d) periodically. For example, a measurement reportevent is triggered in the case that the value of f_(d) exceeds a certainthreshold. Then, the terminal periodically reports thecurrently-measured value of f_(d) (S820). The threshold may bedetermined in a way of computer simulation.

Some methods and processes are apparently disclosed in the abovedescription of the device according to the embodiments of the presentdisclosure. Hereinafter, a wireless communication method according to anembodiment of the present disclosure is described without repeatingdetails described above.

As shown in FIG. 3, a wireless communication method according to anembodiment includes steps S310 to S340.

In step S310, spatial filtering is performed on received signals ofmultiple antennas.

In step S320, based on the spatially-filtered signal of each of theantennas, a frequency offset of the received signal is estimated.

In step S330, a Doppler shift generated by a relative movement between areceiving end and a transmitting end of the received signal and acarrier frequency offset generated by frequency inconsistency of thereceiving end and the transmitting end is estimated based on parametersof the spatial filtering and the estimated frequency offset.

In step S340, a frequency preprocessing is performed on a transmissionsignal of the antenna based on the estimated Doppler shift.

Alternatively or additionally, in step S350, control is performed tofeed back information on the estimated Doppler shift to the transmittingend of the signal.

According to an embodiment, in step S330, the Doppler shift and thecarrier frequency offset are estimated based on a relation that thefrequency offset is a linear combination of the Doppler shift and thecarrier frequency offset.

According to an embodiment, in step S330, the Doppler shift and thecarrier frequency offset may be estimated with a weighted least squaremethod, and weighting is performed based on signal-to-noise ratios ofspatially-filtered signals of multiple antennas.

According to an embodiment, the relation of the linear combination isdetermined based on a signal-to-noise ratio of the spatially-filteredsignal of each of the antennas, a direction angle φ_(n) for the spatialfiltering and a direction angle θ_(R) of the relative movement betweenthe receiving end and the transmitting end of the received signal.

According to an embodiment, estimation values of the Doppler shift andcarrier frequency offset are calculated with an observation matrix and aweighting matrix. The observation matrix is related to the directionangle φ_(n) and the direction angle θ_(R), and the weighting matrix isrelated to the signal-to-noise ratio of the spatially-filtered signal.

According to an embodiment, the signal-to-noise ratio is estimated witha self-correlation method.

According to an embodiment, the observation matrix is predeterminedbased on the direction angle φ_(n) and the direction angle θ_(R).

According to an embodiment, the weighting matrix is determined based onthe signal-to-noise ratio estimated frame-by-frame.

According to an embodiment, in step S320, the frequency offset isestimated with an estimation method based on training sequence or ablind estimation method based on signal statistical information.

According to an embodiment, the Doppler shift and the carrier frequencyoffset are estimated frame-by-frame for a received signal in step S330.

According to an embodiment, the frequency preprocessing in step S340includes: performing a preprocessing by adopting different Doppler shiftestimations for different spatial directions, and weighting atransmission signal with the signal-to-noise ratios estimated by usingthe spatial received signals.

According to an embodiment, in step S350, the information on theestimated Doppler shift further contains: a direction angle for aspatial filtering corresponding to a signal with a highestsignal-to-noise ratio among the spatially-filtered signals.

FIG. 4 shows a process example of a wireless communication methodaccording to another embodiment.

Steps S410 to 450 shown in FIG. 4 are similar to steps S310 to S350described with reference to FIG. 3. In addition, the method according toembodiment further includes step S460 of calibrating a frequency of alocal frequency generator based on the estimated carrier frequencyoffset.

FIG. 5 shows a process example of a wireless communication methodaccording to another embodiment.

Steps S510 to S550 shown in FIG. 5 are similar to steps S310 to S350described with reference to FIG. 3. In addition, the method according tothe embodiment further includes step S560 of performing, by thetransmitting end, a frequency preprocessing on a subsequent transmissionsignal based on information on the estimated Doppler shift.

Besides, FIG. 9 shows a configuration example of an electronic devicefor wireless communication according to an embodiment of the presentdisclosure.

An electronic device 900 according to an embodiment includes a filteringapparatus 910, a first estimation apparatus 920, a second estimationapparatus 930 and a preprocessing/control apparatus 940.

The filtering apparatus 910 is configured to perform spatial filteringon received signals of multiple antennas.

The first estimation apparatus 920 is configured to estimate, based onthe spatially-filtered signal of each of the antennas, a frequencyoffset of the received signal.

The second estimation apparatus 930 is configured to estimate a Dopplershift generated by a relative movement between a receiving end and atransmitting end of the received signal and a carrier frequency offsetgenerated by frequency inconsistency of the receiving end and thetransmitting end, based on parameters of the spatial filtering and theestimated frequency offset.

The preprocessing/control apparatus 940 is configured to perform afrequency preprocessing on a transmission signal of the antenna based onthe estimated Doppler shift, and/or perform control to feed backinformation on the estimated Doppler shift to the transmitting end ofthe signal.

As examples, the steps of the above methods and the modules and/or unitsof the above devices can be realized by software, firmware, hardware orcombinations thereof. In the case where the present disclosure isrealized by software or firmware, a program constituting the softwareimplementing the above methods is installed in a computer with adedicated hardware structure (e.g. a general-purpose computer 1000 shownin FIG. 10) from a storage medium or network, where the computer iscapable of implementing various functions when installed with variousprograms.

In FIG. 10, a central processing unit (CPU) 1001 executes variousprocessing in response to a program stored in a read-only memory (ROM)1002 or a program loaded to a random access memory (RAM) 1003 from astorage section 1008. The data for the various processing of the CPU1001 may be stored in the RAM 1003 as needed. The CPU 1001, ROM 1002 andRAM 1003 are linked with each other via a bus 1004. An input/outputinterface 1005 is also linked to the bus 1004.

The following components are linked to the input/output interface 1005:an input section 1006 (including a keyboard, a mouse and the like), anoutput section 1007 (including displays such as a cathode ray tube(CRT), a liquid crystal display (LCD), a speaker and the like), astorage section 1008 (including a hard disc and the like), and acommunication section 1009 (including a network interface card such as aLAN card, a modem and the like). The communication section 1009 performscommunication processing via a network such as the Internet. A driver1010 may also be linked to the input/output interface 1005 as needed. Aremovable medium 1011 such as a magnetic disc, an optical disc, amagnetic optical disc and a semiconductor memory may be installed in thedriver 1010 as needed, so that the computer program read therefrom isinstalled in the storage section 1008 as appropriate.

In the case where the foregoing series of processing is achieved withsoftware, programs forming the software are installed from a networksuch as the Internet or a storage medium such as the removable medium1011.

It should be appreciated by those skilled in the art that the storagemedium is not limited to the removable medium 1011 shown in FIG. 10,which has program stored therein and is distributed separately from theapparatus so as to provide the programs to users. The removable medium1011 may be, for example, a magnetic disc (including a floppy disc(registered trademark)), a compact disc (including a compact discread-only memory (CD-ROM) and a digital versatile disc (DVD)), a magnetooptical disc (including a mini disc (MD) (registered trademark)), and asemiconductor memory. Alternatively, the storage medium may be the harddiscs included in the ROM 1002 and the storage section 1008 in whichprograms are stored, and can be distributed to users along with thedevice in which they are incorporated.

In addition, a program product storing machine-readable instructioncodes is further provided according to the embodiments of the presentdisclosure. The method according to the above embodiments of the presentdisclosure can be performed when the instruction codes are read andexecuted by a machine.

Accordingly, a storage medium for carrying the program product in whichmachine-readable instruction codes are stored is also provided in thepresent disclosure. The storage medium includes but is not limited to afloppy disc, an optical disc, a magnetic optical disc, a memory card, amemory stick and the like.

The embodiments of the present disclosure may further relate to thefollowing electronic device. In the case that the electronic device isapplied at a base station side, the electronic device may be implementedas any types of evolved node B (eNB), such as a macro eNB and a smalleNB. The small eNB may be an eNB of a cell having a smaller coveragethan the macro cell, such as a pico-cell eNB, a micro eNB and a home(femto) eNB. Alternatively, the electronic device may be implemented asany other types of base stations, such as a NodeB and a base transceiverstation (BTS). The electronic device may include a main body (alsoreferred to as a base station device) configured to control wirelesscommunication, and one or more remote radio heads (RRHs) arranged at aposition different from a position of the main body. In addition,various types of terminals to be described below can operate as a basestation by temporarily or semi-persistently performing a function of thebase station.

When being applied at a user equipment side, the electronic device maybe implemented as a mobile terminal (such as a smart phone, a panelpersonnel computer (PC), a laptop PC, a portable game terminal, aportable/dongle mobile router and a digital camera) or a vehicleterminal (such as an automobile navigation device). In addition, theelectronic device may be a wireless communication module (such as anintegrated circuit module including one or more wafers) mounted on eachof the above terminals.

[Application Examples of a Terminal Device]

FIG. 11 is a block diagram showing an example of a schematicconfiguration of a smart phone 2500 to which the technology according tothe present disclosure may be applied. The smart phone 2500 includes aprocessor 2501, a memory 2502, a storage 2503, an external connectioninterface 2504, a camera 2506, a sensor 2507, a microphone 2508, anInput apparatus 2509, a display apparatus 2510, a speaker 2511, a radiocommunication interface 2512, one or more antenna switches 2515, one ormore antennas 2516, a bus 2517, a battery 2518 and an auxiliarycontroller 2519.

The processor 2501 may be for example a CPU or a system on chip (SoC),and controls functions of an application layer and an additional layerof the smart phone 2500. The memory 2502 includes RAM and ROM, andstores programs executed by the processor 2501 and data. The storage2503 may include a storage medium such as a semiconductor memory and ahard disk. The external connection interface 2504 refers to an interfaceconnecting an external device (such as a memory card and a universalserial bus (USB) device) to the smart phone 2500.

The camera 2506 includes an image sensor (such as a charge-coupleddevice (CCD) and a complementary metal oxide semiconductor (CMOS)), andgenerates a captured image. The sensor 2507 may include a group ofsensors such as a measurement sensor, a gyroscope sensor, a geomagneticsensor and an acceleration sensor. The microphone 2508 converts voiceinputted to the smart phone 2500 into an audio signal. The Inputapparatus 2509 includes for example a touch sensor configured to detecttouch on a screen of the display apparatus 2510, a keypad, a keyboard, abutton or a switch, and receives an operation or information inputted bythe user. The display apparatus 2510 includes a screen (such as a liquidcrystal display (LCD) and an organic light-emitting diode (OLED)display), and displays an output image of the smart phone 2500. Thespeaker 2511 converts the audio signal outputted from the smart phone2500 into voice.

The radio communication interface 2512 supports any cellularcommunication scheme (such as LTE and LTE-advanced), and performswireless communication. The radio communication interface 2512 maygenerally include for example a BB processor 2513 and an RF circuit2514. The BB processor 2513 may perform for example coding/decoding,modulation/demodulation and multiplexing/demultiplexing, and performvarious types of signal processing for wireless communication.Meanwhile, the RF circuit 2514 may include for example a frequencymixer, a filter and an amplifier, and transmit and receive a wirelesssignal via the antenna 2516. The radio communication interface 2512 maybe a chip module on which the BB processor 2513 and the RF circuit 2514are integrated. As shown in FIG. 11, the radio communication interface2512 may include multiple BB processors 2513 and multiple RF circuits2514. Although FIG. 11 shows the example in which the radiocommunication interface 2512 includes multiple BB processors 2513 andmultiple RF circuits 2514, the radio communication interface 2512 mayinclude a single BB processor 2513 or a single RF circuit 2514.

In addition to the cellular communication scheme, the radiocommunication interface 2512 may support an additional type of wirelesscommunication scheme, such as a short-distance wireless communicationscheme, a near field communication scheme and a wireless local areanetwork (LAN) scheme. In this case, the radio communication interface2512 may include a BB processor 2513 and an RF circuit 2514 for each ofthe wireless communication schemes.

Each of the antenna switches 2515 switches a connection destination ofthe antenna 2516 between multiple circuits (such as circuits fordifferent wireless communication schemes) included in the radiocommunication interface 2512.

Each of the antennas 2516 includes one or more antenna elements (such asmultiple antenna elements included in the MIMO antenna), and is for theradio communication interface 2512 to transmit and receive a wirelesssignal. As shown in FIG. 11, the smart phone 2500 may include multipleantennas 2516. Although FIG. 11 shows the example in which the smartphone 2500 includes multiple antennas 2516, the smart phone 2500 mayinclude a single antenna 2516.

In addition, the smart phone 2500 may include antennas 2516 fordifferent wireless communication schemes. In this case, the antennaswitch 2515 may be omitted in the configuration of the smart phone 2500.

The processor 2501, the memory 2502, the storage 2503, the externalconnection interface 2504, the camera 2506, the sensor 2507, themicrophone 2508, the Input apparatus 2509, the display apparatus 2510,the speaker 2511, the radio communication interface 2512 and theauxiliary controller 2519 are connected with one another via the bus2517. The battery 2518 supplies power to the modules of the smart phone2500 shown in FIG. 11 via a feed line. The feed line is partially shownwith a dashed line in the figure. The auxiliary controller 2519, forexample, operates a minimum necessary function of the smart phone 2500in a sleep mode.

In the smart phone 2500 shown in FIG. 11, at least a portion of thefunctions of the units or modules described with reference to FIGS. 1, 2and 6 may be implemented by the processor 2501 or the auxiliarycontroller 2519. For example, an electric power consumption of thebattery 2518 can be reduced in a way of performing a portion offunctions of the processor 2501 by the auxiliary controller 2519. Inaddition, the processor 2501 or auxiliary controller 2519 can perform atleast a portion of functions of the units or modules described withreference to FIGS. 1, 2 and 6 by executing programs stored in the memory2502 or storage 2503.

[Application Examples of a Base Station]

FIG. 12 is a block diagram showing an example of a schematicconfiguration of an eNB to which the technology according to the presentdisclosure can be applied. An eNB 2300 includes one or more antennas2310 and a base station device 2320. The base station device 2320 may beconnected to each of the antennas 2310 via a radio frequency (RF) cable.

Each of the antennas 2310 includes one or more antenna elements (such asmultiple antenna elements included in a multiple-input multiple-output(MIMO) antenna), and is for the base station device 2320 to transmit andreceive a wireless signal. As shown in FIG. 12, the eNB 2300 may includemultiple antennas 2310. For example, the multiple antennas 2310 may becompatible with multiple frequency bands used by the eNB 2300. AlthoughFIG. 12 shows the example in which the eNB 2300 includes multipleantennas 2310, the eNB 2300 may include a single antenna 2310.

The base station device 2320 includes a controller 2321, a memory 2322,a network interface 2323 and a radio communication interface 2325.

The controller 2321 may be for example a CPU or a DSP, and operatesvarious functions of a high layer of the base station device 2320. Forexample, the controller 2321 generates a data package based on data of asignal processed by the radio communication interface 2325, andtransfers the generated package via the network interface 2323. Thecontroller 2321 may bundle data from multiple baseband processors togenerate a bundling package, and transfers the generated bundlingpackage. The controller 2321 may have a logical function for performingthe following controls: radio resource control, radio bearer control,mobility management, admission control and scheduling. The control maybe performed in conjunction with a nearby eNB or core network node. Thememory 2322 includes RAM and ROM, and stores programs to be executed bythe controller 2321 and various types of control data (such as aterminal list, transmission power data and scheduling data).

The network interface 2323 is a communication interface for connectingthe base station device 2320 to a core network 2324. The controller 2321may communicate with a core network node or another eNB via the networkinterface 2323. In this case, the eNB 2300 may be connected with thecore network node or other eNBs via a logic interface (such as aninterface S1 and an interface X2). The network interface 2323 may be awired communication interface or a radio communication interface forwireless backhaul routing. If the network interface 2323 is a radiocommunication interface, the network interface 2323 may use a frequencyband for wireless communication higher than that used by the radiocommunication interface 2325.

The radio communication interface 2325 supports any cellularcommunication scheme (such as Long Term Evolution (LTE) andLTE-advanced), and provides a wireless connection to a terminal locatedin a cell of the eNB 2300 via the antenna 2310. The radio communicationinterface 2325 may generally include for example a baseband (BB)processor 2326 and an RF circuit 2327. The BB processor 2326 may performfor example coding/decoding, modulation/demodulation andmultiplexing/demultiplexing, and performs various types of signalprocessing of layers (such as L1, Media Access Control (MAC), Radio LinkControl (RLC) and Packet Data Convergence Protocol (PDCP)). Instead ofthe controller 2321, the BB processor 2326 may have a portion or all ofthe above logical functions. The BB processor 2326 may be a memorystoring communication control programs, or a module including aprocessor and a related circuit which are configured to executeprograms. The function of the BB processor 2326 may be changed when theprograms are updated. The module may be a card or blade inserted intothe slot of the base station device 2320. Alternatively, the module maybe a chip mounted on the card or the blade. Meanwhile, the RF circuit2327 may include for example a frequency mixer, a filter and anamplifier, and transmit and receive a wireless signal via the antenna2310.

As shown in FIG. 12, the radio communication interface 2325 may includemultiple BB processors 2326. For example, the multiple BB processors2326 may be compatible with the multiple frequency bands used by the eNB2300. As shown in FIG. 12, the radio communication interface 2325 mayinclude multiple RF circuits 2327. For example, the multiple RF circuits2327 may be compatible with multiple antenna elements. Although FIG. 12shows an example in which the radio communication interface 2325includes multiple BB processors 2326 and multiple RF circuits 2327, theradio communication interface 2325 may include a single BB processor2326 or a single RF circuit 2327.

In the eNB2300 shown in FIG. 12, at least a portion of functions of theunits or modules described in conjunction with FIGS. 1, 2 and 7 may berealized by the controller 2321. For example, the controller 2321 mayperform at least a portion of functions of the units or modulesdescribed in conjunction with FIGS. 1, 2 and 7 by performing programsstored in the memory 2322.

[Application Example of an Automobile Navigation Device]

FIG. 13 is a block diagram showing an example of a schematicconfiguration of an automobile navigation device 1320 to which thetechnology according to the present disclosure may be applied. Theautomobile navigation device 1320 includes a processor 1321, a memory1322, a global positioning system (GPS) module 1324, a sensor 1325, adata interface 1326, a content player 1327, a storage medium interface1328, an Input apparatus 1329, a display apparatus 1330, a speaker 1331,a radio communication interface 1333, one or more antenna switches 1336,one or more antennas 1337 and a battery 1338.

The processor 1321 may be for example a CPU or an SoC, and controls anavigation function and additional function of the automobile navigationdevice 1320. The memory 1322 includes RAM and ROM, and stores programsexecuted by the processor 1321 and data.

The GPS module 1324 determines the location of the automobile navigationdevice 1320 (such as latitude, longitude and height) with a GPS signalreceived from a GPS satellite. The sensor 1325 may include a group ofsensors such as a gyroscope sensor, a geomagnetic sensor and an airpressure sensor. The data interface 1326 is connected to for example anon-board network 1341 via a terminal not shown, and acquires datagenerated by the vehicle (such as vehicle speed data).

The content player 1327 reproduces contents stored in a storage medium(such as CD and DVD) which is inserted into the storage medium interface1328. The Input apparatus 1329 includes for example a touch sensorconfigured to detect touch on a screen of the display apparatus 1330, abutton or a switch, and receives an operation or information inputted bythe user. The display apparatus 1330 includes a screen of a display suchas an LCD or OLED, and displays an image of navigation function or thereproduced contents. The speaker 1331 outputs voice of the navigationfunction or the reproduced contents.

The radio communication interface 1333 supports any cellularcommunication scheme (such as LTE and LTE-advanced), and performswireless communication. The radio communication interface 1333 maygenerally include for example a BB processor 1334 and an RF circuit1335. The BB processor 1334 may perform for example coding/decoding,modulation/demodulation and multiplexing/demultiplexing, and performvarious types of signal processing for wireless communication.Meanwhile, the RF circuit 1335 may include for example a frequencymixer, a filter and an amplifier, and transmit and receive a wirelesssignal via the antenna 1337. The radio communication interface 1333 maybe a chip module on which the BB processor 1334 and the RF circuit 1335are integrated. As shown in FIG. 13, the radio communication interface1333 may include multiple BB processors 1334 and multiple RF circuits1335. Although FIG. 13 shows the example in which the radiocommunication interface 1333 includes multiple BB processors 1334 andmultiple RF circuits 1335, the radio communication interface 1333 mayinclude a single BB processor 1334 or a single RF circuit 1335.

In addition to the cellular communication scheme, the radiocommunication interface 1333 may support an additional type of wirelesscommunication scheme, such as a short-distance wireless communicationscheme, a near field communication scheme and a wireless LAN scheme. Inthis case, the radio communication interface 1333 may include a BBprocessor 1334 and an RF circuit 1335 for each of the wirelesscommunication schemes.

Each of the antenna switches 1336 switches a connection destination ofthe antenna 1337 between multiple circuits (such as circuits fordifferent wireless communication schemes) included in the radiocommunication interface 1333.

Each of the antennas 1337 includes one or more antenna elements (such asmultiple antenna elements included in the MIMO antenna), and is for theradio communication interface 1333 to transmit and receive a wirelesssignal. As shown in FIG. 13, the automobile navigation device 1320 mayinclude multiple antennas 1337. Although FIG. 13 shows the example inwhich the automobile navigation device 1320 includes multiple antennas1337, the automobile navigation device 1320 may include a single antenna1337.

In addition, the automobile navigation device 1320 may include antennas1337 for different wireless communication schemes. In this case, theantenna switch 1336 may be omitted in the configuration of theautomobile navigation device 1320.

The battery 1338 supplies power to the modules of the automobilenavigation device 1320 shown in FIG. 13 via a feed line. The feed lineis partially shown with a dashed line in the drawing. The battery 1338accumulates the power provided from the vehicle.

In the automobile navigation device 1320 shown in FIG. 13, the processor1321 may perform at least a portion of functions of the units describedin conjunction with FIG. 1 and FIG. 2 by executing programs stored inthe memory 1322.

The technology according to the present disclosure may be furtherimplemented as an on-board system (or a vehicle) 1340 including one ormore of the automobile navigation device 1320, the on-board network 1341and a vehicle module 1342. The vehicle module 1342 generates vehicledata (such as a vehicle speed, a motor speed and fault information) andoutputs the generated data to the on-board network 1341.

In the above description of the embodiments of the present disclosure,features that are described and/or illustrated with respect to oneembodiment may be used in the same way or in a similar way in one ormore other embodiments, may be combined with or instead of the featuresof the other embodiments.

It should be emphasized that the term “comprises/comprising” used inthis specification refers to the presence of features, elements, stepsor components, but does not preclude the presence or addition of one ormore other features, elements, steps or components.

In the above embodiments and examples, the steps and/or units arerepresented with reference numbers consists of numbers. It should beunderstood by those skilled in the art that, these reference numbers areonly for convenience of the description and drawing, and are notintended to represent an order of the steps and units or to representany other constraint.

In addition, the methods according to the present disclosure are notlimited to be executed in the time sequence described in thespecification, and may be executed in other time sequence, parallel orindependently. Therefore, the execution order of the method described inthe specification is not intended to limit the technical scope of thepresent disclosure.

While the present disclosure has been disclosed with reference to thespecific embodiments thereof, it should be understood that all of theabove embodiments and examples are illustrative rather than restrictive.Those skilled in the art will appreciate that various modifications,improvements and equivalents are possible, without departing from thespirit and scope of the appended claims. These modifications,improvements or equivalents are intended to be included within theprotection scope of the present disclosure.

1. An electronic device for wireless communication, comprising: at leastone processor configured to perform spatial filtering respectively onreceived signals of a plurality of antennas to form correspondingspatially-filtered signals; estimate, based on the correspondingspatially-filtered signal of each of the antennas, a frequency offset ofthe corresponding received signal; estimate, based on parameters of thespatial filtering and the estimated frequency offset, a Doppler shift ofthe received signal caused by a relative movement between a receivingterminal and a transmitting terminal and a carrier frequency offsetcaused by frequency inconsistency of equipment at the receiving terminaland at the transmitting terminal; and perform frequency preprocessing ona transmission signal to be transmitted based on the estimated Dopplershift, wherein at least the estimated Doppler shift is based on a linearcombination of the Doppler shift and carrier frequency offset, and thelinear combination includes a direction angle θ_(R) of a relativemovement between the receiving terminal and the transmitting terminal ofthe received signal.
 2. The electronic device according to claim 1,wherein the at least one processor is further configured estimate thecarrier frequency offset based on a relation that the frequency offsetis a linear combination of the Doppler shift and the carrier frequencyoffset.
 3. The electronic device according to claim 2, wherein theDoppler shift and the carrier frequency offset are estimated by using aweighted least square method, and wherein the weighting is performedbased on signal-to-noise ratios of the respective spatially-filteredsignals of the plurality of antennas.
 4. The electronic device accordingto claim 3, wherein the relation of the linear combination is determinedbased on the signal-to-noise ratio of the spatially-filtered signal ofeach of the plurality of antennas, a direction angle ϕ_(n) for thespatial filtering and the direction angle θ_(R) of the relative movementbetween the receiving end and the transmitting end of the receivedsignal.
 5. The electronic device according to claim 4, wherein estimatesof the Doppler shift and the carrier frequency offset are calculatedusing an observation matrix and a weighting matrix, wherein theobservation matrix is related to the direction angle ϕ_(n) and thedirection angle θ_(R), and the weighting matrix is related to thesignal-to-noise ratio of the spatially-filtered signal.
 6. Theelectronic device according to claim 5, wherein the observation matrixis predetermined based on the direction angle ϕ_(n) and the directionangle θ_(R).
 7. The electronic device according to claim 5, wherein theweighting matrix is determined based on the signal-to-noise ratioestimated frame-by-frame.
 8. The electronic device according to claim 1,wherein the frequency offset is estimated by using an estimation methodbased on training sequence or a blind estimation method based on signalstatistical information.
 9. The electronic device according to claim 3,wherein the signal-to-noise ratio is estimated by using aself-correlation method.
 10. The electronic device according to claim 1,wherein the at least one processor is configured to estimate the Dopplershift and the carrier frequency offset frame-by-frame for the receivedsignal.
 11. The electronic device according to claim 1, wherein the atleast one processor is configured to perform the frequency preprocessingvia adoption of different Doppler shift estimations for differentspatial directions, and weighting the transmission signal withsignal-to-noise ratios estimated for the spatial received signals. 12.The electronic device according to claim 1, wherein the at least oneprocessor is further configured to: calibrate a frequency of a localfrequency generator in at least one of the equipment at receivingterminal and the transmitting terminal based on the estimated carrierfrequency offset.
 13. The electronic device according to claim 1,wherein the equipment at the receiving terminal is configured tofeedback information on the estimated Doppler shift, the informationincluding a direction angle of spatial filtering corresponding to thesignal with a highest signal-to-noise ratio among the spatially-filteredsignals.
 14. A wireless communication method, comprising: performingwith circuitry spatial filtering respectively on received signals of aplurality of antennas to form corresponding spatially-filtered signals;estimating, based on the corresponding spatially-filtered signal of eachof the antennas, a frequency offset of the corresponding receivedsignal; estimating, based on parameters of the spatial filtering and theestimated frequency offset, a Doppler shift of the received signalcaused by a relative movement between a receiving terminal and atransmitting terminal and a carrier frequency offset caused by frequencyinconsistency of equipment at the receiving terminal and at thetransmitting terminal; and performing frequency preprocessing on atransmission signal to be transmitted based on the estimated Dopplershift, wherein at least the estimated Doppler shift is based on a linearcombination of the Doppler shift and carrier frequency offset, and thelinear combination includes a direction angle θ_(R) of a relativemovement between the receiving terminal and the transmitting terminal ofthe received signal.
 15. The method according to claim 14, wherein thecarrier frequency offset is estimated based on a relation that thefrequency offset is a linear combination of the Doppler shift and thecarrier frequency offset.
 16. The method according to claim 15, whereinthe Doppler shift and the carrier frequency offset are estimated byusing a weighted least square method, and wherein the weighting isperformed based on signal-to-noise ratios of the respectivespatially-filtered signals of the plurality of antennas.
 17. The methodaccording to claim 14, wherein estimates of the Doppler shift and thecarrier frequency offset are calculated using an observation matrix anda weighting matrix, wherein the observation matrix is predeterminedbased on a direction angle ϕ_(n) for the spatial filtering and thedirection angle θ_(R) of the relative movement between the receiving endand the transmitting end of the received signal.
 18. The methodaccording to claim 14, wherein estimates of the Doppler shift and thecarrier frequency offset are calculated using an observation matrix anda weighting matrix, wherein the weighting matrix is determined based onthe signal-to-noise ratio of the spatially filtered signal estimatedframe-by-frame.
 19. The method according to claim 14, wherein theDoppler shift and the carrier frequency offset are estimatedframe-by-frame for the received signal.
 20. The method according toclaim 14, further comprising sending feedback information from thereceiving terminal to the transmitting terminal, wherein the informationincludes a direction angle of spatial filtering corresponding to thesignal with a highest signal-to-noise ratio among the spatially-filteredsignals.